That said, where are you seeing these? I just looked through the back-end list, and, it looks like the achievements only go up to level 9 there.

The list of achievements for Skyward Collapse in Steam still shows them.

On granting the achievements:Aren't they simply triggered in Steam based on what the application says? if so you could simply grant the Arcen incarnation of the respective achievements to every profile that has the necessary amounts of wins in the next patch...Steam should follow suite then, shouldn't it?

These definitely aren't on the back-end list. I think they are on the list you saw because several folks have achieved it. That said, there's nothing we can do on our end to get rid of them that I'm aware of. Sorry